Support for control slide of core and mold making machine



March 23, 1965 F. HANSBERG 3,174,196

SUPPORT FOR CONTROL SLIDE OF CORE AND MOLD MAKING MACHINE Filed March 21, 1963 4 Sheets-Sheet 1 Fig.1

IN VE N TOR FR/rz f/fiwsanw BY MM 'Hrromvsrs March 23, 1965 F. HANSBERG 3,174,196

SUPPORT FOR CONTROL SLIDE OF CORE AND MOLD MAKING MACHINE Filed March 21, 1963 4 Sheets-Sheet 2 Fig.2

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INVENTOR BY M Hrromvsrs March 23, 1965 F. HANSBERG 4 3,174,196

SUPPORT FOR CONTROL SLIDE OF CORE AND- MOLD MAKING MACHINE Filed March 21, 1963 4 Sheets-Sheep 3 I l l i I )l 'l \i 44 1 45 40 4 INVE N TOR #721 7'2 669N68 BY HM wob HT'T'OR/ViVS March 23, 1965 F. HANSBERG 3,174,196

SUPPORT FOR CONTROL suns OF coma AND MOLD MAKING MACHINE Filed March 21, 1963 4 Sheets-Sheet 4 Fig.5 4 2 22 \\\\1 i K -40 s 51 I I r I. 1 X

INVENTOR FR/rz //HN 8R6 United States Patent 3,174,196 SUPPORT FOR CONTROL SLIDE 0F CORE AND MOLD MAKING MACHINE Fritz Hansberg, Via Archirola 15, Modena, Italy Filed Mar. 21, 1963, Ser. No. 266,849 Claims priority, application Italy, Mar. 23, 1962, 21,747/ 62, Patent 666,853 9 Claims. (Cl. 22-10) The invention relates to a machine for investing mold boxes, etc. with a slurry, and more particularly to a machine for investing core and mold boxes with a slurry for the purpose of producing molds and cores as they are used in foundries.

There are known in practice machines in which the slurry such as molding sand is supplied to a supply container in the machine in which container air pressure is built up controlled by a pressure air control valve. The slurry is discharged from the supply container into the box to be invested. Various types of such mold and core making machines operating with pressure air are lmown. They are two basically different types of machines and modes of operation, to wit: the so-called true blowing machines in which a mixture of air and molding sand is blown out and the so-called shooting machines in which the molding sand is abruptly forced into the box to be invested without previously mixing the molding sand with air. To state it differently, in one type of machine the siurry is made flowable by mixing it with air, whereas in the other type machine the slurry remains substantially compacted and is propelled out of the machine in the form of a substantially solid core, somewhat similar to the manner in which a pellet is shot out of an air-rifle. Machines of the shooting type are more fully described in U. S. Patents 2,793,409 and 2,983,971.

The invention is particularly useful in connection with machines using the shooting principle.

In all mold and core making machines the supply container for the molding sand or other slurry must be replenished from time to time. To control such replenishing of the supply of slurry a feed control slide is usually provided which can be slid into and out of a position closing the supply container at its top side. A feed hopper mounted above the supply container serves to direct a new supply of slurry into the container when the control slide is moved into the open position. With shooting machines the hopper is usually in the form of a vibratory chute.

In shooting machines the supply container of the machine must generally be recharged after each operation and since the involved quantities of slurry are rather large, the hopper must be correspondingly large and is continuously refilled. Control of the charging of the machine with slurry and, in particular, the control of the closing and opening movements of feed control slide is eflected with small machines manually and with large machines, especially shooting machines automatically.

The continuous opening and closing of the feed control slide causes a considerable wear and tear of the slide. Such wear and tear has become even more pronounced since the replacement of the previously customary plastic stiff molding slurries by semi-fluid slurries, such as flowable molding sand, since the grains of such sands can creep readily into the narrow gaps at the guides for the slide and are highly abradant. The wear and tear on the feed control slide is particularly marked with shooting machines since in machines of this kind the slide in its closed position must support the total weight of the hopper and slurry contained therein and the slider is opened and closed after each shooting operation, usually at time intervals of to 20 seconds. The fully automatic operatrolling guide means, especially rollers, the slide no longer ing mold or core forming lines, opening and closing of the slide may be effected more than a half-million times per year. Due to such continual wear in automatic operation the feed control slide must be renewed rather frequently, which entails stopping of the entire mold and core forming line in a fully automatic and continuously operating assembly.

It is a broad object of the present invention to provide a machine in'which the feed control slide is so arranged that is subjected to practically no wear and tear.

The aforementioned object and other objects, features and advantages which will be pointed out hereinafter are attained in a machine for investing mold and core boxes or offer mold boxes with a slurry by guiding the feed control slide into and out of its position closing the container for the slurry by means of rolling guide means. These rolling guide means may be in the form of balls, but the use of rollers has been found to be generally more advantageous.

According to one embodiment of the invention the guide rollers for the slide are horizontally disposed and rotatable about a vertical axis whereby the slide rests upon and rolls along surfaces of the rollers. It has been found that the slide continuously wipes off any sand particles which may adhere to the surfaces of the rollers with which the slide is in contact as it moves into and out of its closing position. In other words, the roller and slide assembly is self-cleaning. The guide rollers for the slide are preferably supported by means of a suspension mounting as such mountings require a minimum of space for mounting the slide. The rollers which are horizontally disposed but rotate about a vertical axis, have preferably lateral shoulders along which the slide can move.

Due to the mounting of the feed control slide on such rests-directly upon the head portion of the slurry container in the machine, but is separated from this portion by a gap of a few tenths of a millimeter. This gap must be sealed off when the slide is closed as otherwise part of the pressure air by which the slurry is propelled out of the machine and into the box to be invested would escape through the gap between the slide and the head of the slurry container whereby part of the energy of the pressure air would be lost.

It has been found that a flexible sealing means activated by pressure air is particularly suitable for coaction with a control slide mounted on guide rollers. The sealing means is subjected to air pressure when the slide is in its position closing. the sand container of the machine whereby the aforementioned gap between the slide and the head of the sandcontainer is sealed- In the aforedescribed arrangement grains of sand will creep into the gap between the slide and the head of the sand container. Such creeping is acceptable as far as the sealing means. To prevent creeping of sand particles around the sealing means and penetration of the sand into the interior of the sealing means and from there into the air control valves, -the sealing means are preferably secured to a mounting surface by means of pressure rings. The sealing means are elastically deformable and to this end preferably in the form of a tubular member which is expandible by being filled with pressure air, thus bridging and sealing the aforedescribed gap underneath the slide supported by the guide rollers. A pressure sealing having lateral flanges is particularly suitable as such flanges permit a convenient and airtight mounting of the sealing tube by means of the pressure rings.

In the accompanying drawing a preferred embodiment of the invention is shown by way of illustration and not by way of limitation.

Patented Mar. 23, 1965 In the drawing:

FIG. 1 is a diagrammatic view of a core or mold making machine according to the invention.

FIG. 2, is a sectional view of the headportion of the machine on an enlarged scale.

FIG. 3 is a further enlarged sectional view of the upper part of FIG. 2, the right half of the section showing the support of the feed control slide by rolling guide means and the left side of the section showing the sealing means for the slide.

FIG. 4 is a plan view of FIG. 3, partly in section.

FIG. 5 is a detailed view of the sealing means for the feed control slide on an enlarged scale, the slide being shown in its position closing the slurry container of the machine and the sealing means sealing the slide, and

FIG. 6 is a sectional view similar to FIG. 5 but showing. the slidein its open position and the sealing means in the non-sealing condition.

Referring first to FIG. 1 in detail, the machine shown in this figure is a core and mold making machine of the slurry shooting type as previously described. The illustrated machine is a large type machine and equipped with means for supplementary or after pressing of the slurry to be invested in a box.

The. exemplified machine comprises a base, plate 10 which supports an upright frame 1 and a lifting cylinder 11 which serves to lift and lower a machine table 14 upon which is placed a box (not shown) to be invested. The head portion 2 of the machine is mounted on frame 1 and accommodates a storage chamber for the pressure air eflecting the shot like ejection of the slurry such as sand and a slurry supply container, as will bev more fully described in conjunction with other figures. At the lower end of the supply container the head portion 2 mounts the shooting head 6. The shooting head in turn supports a vertically displaceable frame 8 for supplementary or after pressing of the slurry. The frame is locked in a predetermined vertical position in reference to the shooting head, or released from this position by means of four hydraulic cylinder-piston units 15 which are controlled by a pneumatic automatic control device mounted in the head portion 2 and connected to the cylinder-piston units by means of a conduit 13. An automatically controlled venting valve 9 of the machine is connected by a pressure air conduit 16 to sealing means for sealing supplementary pressing frame 8 at the shooting head 6. A hopper 27 is mounted on top of head portion 2 and the supply of slurry such as sand is fed from the hopper to the slurry container in the machine under the control of a feed control slide 28. Slide 28 is guided on horizontal guide rolls 40-and may be moved into and out of a position closing discharge of slurry from hopper 27 into the supply container by means of a pressure air operated cylinder assembly 29 mounted on the frame or the head portion of the machine.

The head portion 2 is hollow, and according to FIG. 2 a cylindrical supply container 3 for sand or other slurry material is inserted into head portion 2 from below. Container 3. is secured in position by means of a flange 5 and fastening means such as bolts extended through theflange. An annular chamber 12 defined in headv portion.2 by container 3. serves as a storage chamber for the pressure air used to effect the. abrupt or shot-like ejection of the slurry from the machine and, into the box to. be invested- The storage chamber 12- for the pressure. air is continued in head portion- 2 as far as the wall of the framestructure 1. Supply container 3 is continued adjacent to the upper part of the annular chamber 12 bya. ring-shaped partition. wall 32 whereby an annular gap 31 is left between partition wall 32 and the upper edge of container 3. Wall 32 together with a cylinder 24 of somewhat larger diameter than wall 32 defines an annular cylindrical space 23 in which a ring valve 18 is vertically movable. Ring valve 18 is subjected at its upper surface 26 to control pressure air supplied to space 23 by a control air conduit (not shown) while the lower surface 25 of the valve is exposed to the pressure of the air used for ejection of the slurry from the machine and stored in chamber 12. The lower surface 25 of valve 18 mounts a seal 21 with which the valve is seated upon the top end 20. of the supply container 3. As a result the. lower surface 25 of valve 18 is exposed to the pressure air stored in annular chamber 12 by a smaller area than the area which the upper surface 26 offers to .the control pressure air contained in the annular space 23. Consequently the pressure air in space 23 is capable of pressing the valve 18 strongly against the top end 20 of supply container 3 against the pressure of the pressure air stored in chamber 12, whereby the annular gap 31 is sealed against the interior of container 3. However, when space 23 is vented the pressure air stored in annular chamber 12 forces valve 18 abruptly into its upper limit position and the pressure air can then flow from chamber 12 into the interior of container 3 through annular gap 31.

A perforated insert 4- is fitted in the interior of supply container 3. The insert defines between its outer wall and the inner wall of container 3 an annular space 30 into which pressure air from the storage chamber 12 can fioW through ring gap 31 when valve 18 for controlling the expulsion of sand from the machine is actuated. The pressure air will then flow downwardly in space 30. Insert 4 has in its wall along nearly the entire height thereof a plurality of short vertical slits 34, the width of which may be a fraction of a millimeter. The upper end of insert 4 includes a plurality of short horizontal slits 33 which also have a width of a fraction of a millimeter.

As it is evident, the pressure air stored in annular chamber 12 for effecting expulsion of the sand, when flowing downwardly in space 30 upon opening of gap 31 by operation of valve 18, will penetrate through slits 34 into insert 4 and act upon the compacted sand therein in radial direction. In addition, the pressure air will enter the insert through the upper horizontal slits 33 and act upon the top side of the sand in insert 4 in axial direction. As a result of the radial action of the pressure air the compacted mass or core of sand will be somewhat radially compressed so that it becomes free of the inner Wall of insert 4 and is hence in effect momentarily floating, thus facilitating the shot-like expulsion of the sand from the machine. After the sand is expelled from the machine, container 3 is vented by means of the automatically controlled venting valves 9 disposed on opposite sides of head portion 2.

The automatic recharging of supply container 3 is initiated by a diaphragm controlled valve 17 disposed within container 3. The valve controls the movements of feed control slide 28 closing and opening respectively the open top side of container 3 and is controlled by a suitable automatic control system (not shown). The slide 28 is guided on horizontally disposed rollers 40 and is sealed from below in its closing position by means of a pressure air seal 22.

The bottom end of container 3 mounts a shooting head 6. This shooting head, which may be fixedly or detachably mounted and serves to invest core or mold boxes with slurry, is provided with a grid shaped plate 55 including slot type nozzles 7. The slurry such as sand which is compacted in insert 4 of container 3 is driven through nozzles 7 into a box (not shown) placed on table 14.

Shooting head 6 is equipped with a vertically movable frame 8 for applying a supplementary or after pressure to the slurry in the box. The-vertical surfaces along which frame 8 is movable may be sealed by means of a pressure air seal which is connected by a pressure air conduit 16 either with venting valve 9 and thus with the pressure air control conduit 16a thereof (to the right in FIG. 2), or directly with the control air conduit 16a of venting valve 9, as is shown at the left side of FIG. 2.

FIGS. 3 and 4 show more in detail the guidance of feed control slide 28 on rolling guide means shown as horizontally disposed guide rollers 40. These rollers are rotatable about vertical pins a1 and suspended by means of these pins from a head plate 42. To facilitate rotation of the rollers on the pins suitable bearings such as deepgroove type radial ball bearings may be provided. Rollers 40 are formed with peripheral shoulders 44 and slide 23 is supported by the horizontal surface 45 of the shoulders and slides along this surface. As a result of the slider movement any slurry particles which may adhere to or accumulate on surfaces 45 and 46 of the rollers are continuously wiped off, thereby effecting a continuously selfcleaning of rollers 49.

As shown in FIGS. 3, 5 and 6, a flexible sealing 22 is provided at the surface 35 of head portion 2 to seal slider 2% against the surfaces along which it moves. Seal 22 is preferably a pressure air seal. It is shown as a ring tube from which extend two lateral flanges 36. The sealing tube is secured airtight by means of these flanges and two pressure rings 37 and 38 to a mounting ring 39. To obtain a strong grip between flanges 36 and pressure rings 37 and 38 the latter are formed at the lower side with wedge shaped pressure surfaces 47 and 48 which are forced into flanges 36 when the pressure rings are tightened against the flanges. To prevent deformation of the sealing tube toward its midportion when flanges 36 are compressed by rings 37 and 35, a ring shaped rib 49 is provided on mounting 39. This rib protrudes into the interior 50 of the sealing tube thus limiting deformation of the same.

Slide 23 when moving into and out of its position closing container 3 is spaced from the upper side of pressure rings 37 and 38 only by a very small gap .9 generally in the order of a few tenths of a millimeter. Experience shows that sand tends to creep into the gap .9 and to accumulate gradually therein, thereby causing a jamming of slide 23 and also wear and tear at the slide. To prevent, or at least to impede, such creeping of sand it is essential that the upper surfaces of pressure rings 37 and 38 facing the slide are smooth, that is not interrupted by any inserted screw heads or nuts. As is shown in the figures, the pressure rings are secured to the mounting ring 39 by means of screws 51 inserted from below, thus pre serving the integrity of the upper surfaces of rings 37 and 38. When the sealing tube is in its relaxed condition, that is, not filled with pressure air, the upper edges of rings 37 and 38 are higher than the top of sealing tube 22 by the distance it which may be about 0.5 millimeter. Pressure air may be applied to sealing tube 22 through a pressure air duct 52 which is connected through an air distrib uting duct 53 to the interior 50 of the seal. The sealing tube is made of a suitable flexible material, such as rubber, and is hence elastically expandible by air pressure within the tube. Due to the expansion of the sealing tube the same will close the gap .9 between slide 28 and the upper surface of rings 37 and 3S and also press slide 28 from below against the head plate 42, thus sealing the open top side of container 3 (see FIG. 5). Since the seal is pressed airtight against mounting ring 39 by means of flanges 36 and pressure rings 37 and 38, the sand can readily penetrate into gap s up to pressure seal 22, but cannot creep past the pressure seal mounting and, in particular, not enter into the inner space 50 of the seal, so that there is no danger that sand will reach through duct 52 the rather sensitive pressure control valves and jam the same when the pressure seal 22 is released.

While the invention has been described in detail with respect to a certain now preferred example and embodiment of the invention, it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

I claim:

1. A machine for investing mold and core boxes with a slurry, said machine comprising a supply container for slurry open at its top, pressure air operated means for expelling slurry from said container and into boxes to be invested, a feed control slide slidable into and out of a position closing said supply container, and stationary rolling guide means guiding and supporting said slide when and While sliding into and out of said position, said guide means including rollers having horizontally disposed surfaces supporting said slide and being rotatable about vertical axes.

2. A machine according to claim 1 wherein vertically mounted shafts support said rollers.

3. A machine according to claim 2 and comprising mounting means from which said shafts depend.

4. A machine according to claim 1 wherein said rollers each have a laterally protruding shoulder, said slide being slidably guided on said shoulders and en aging peripheral side wall portions of the rollers to strip slurry accumulating on said shoulders.

5. A machine according to claim 1 wherein said rollers support said slide spaced apart from the top of the container to form a narrow annular gap therebetween, and comprising an elastically expandable sealing means mounted at the top of the supply container encompassing the same and closing said gap for sealing the container against the slide in the open position of the latter.

6. A machine according to claim 5 wherein said sealing means is a ring-shaped pressure operated sealing means, and means for supplying pressure fluid to the sealing means, said pressure fluid supply means being activated in the closing position of the slide.

7. A machine according to claim 6 wherein said pressure sealing means comprises a hollow and elastic member expandable by feeding pressure fluid into said member to effect sealing action.

8. A machine according to claim 5 wherein said sealing means comprise lateral extensions a mounting surface and ring shape pressure members engaging said extensions to Eecure the same to said mounting surface with an airtight 9. A machine according to claim 8 wherein said sealing means comprises a flanged tube, the flanges of the tube being eld by said pressure members in airtight engagement with said mounting surface.

References Cited by the Examiner UNITED STATES PATENTS 2,240,049 4/41 Murphy 251l 2,978,759 4/61 Hansberg 22-10 3,089,205 5/63 Ellms 22-10 MICHAEL V. BRINDISI, Primary Examiner. MARCUS U. LYONS, Examiner. 

1. A MACHINE FOR INVESTING MOLD AND CORE BOXES WITH A SLURRY, SAID MACHINE COMPRISING A SUPPLY CONTAINER FOR SLURRY OPEN AT ITS TOP, PRESSURE AIR OPERATED MEANS FOR EXPELLING SLURRY FROM SAID CONTAINER AND INTO BOXES TO BE INVESTED, A FEED CONTROL SLIDE SLIDABLE INTO AND OUT OF A POSITION CLOSING SAID SUPPLY CONTAINER, AND STATIONARY ROLLING GUIDE MEANS GUIDING AND SUPPORTING SAID SLIDE WHEN AND WHILE SLIDING INTO AND OUT OF SAID POSITION, SAID GUIDE MEANS INCLUDING ROLLERS HAVING HORIZONTALLY DISPOSED SURFACES SUPPORTING SAID SLIDE AND BEING ROTATABLE ABOUT VERTICAL AXES. 